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Population pyramid. A population pyramid (age structure diagram) or " age-sex pyramid " is a graphical illustration of the distribution of a population (typically that of a country or region of the world) by age groups and sex; it typically takes the shape of a pyramid when the population is growing. [1] Males are usually shown on the left and ...
In statistics, dispersion (also called variability, scatter, or spread) is the extent to which a distribution is stretched or squeezed. [1] Common examples of measures of statistical dispersion are the variance, standard deviation, and interquartile range. For instance, when the variance of data in a set is large, the data is widely scattered.
Figure 1: The left graph shows a probability density function. The right graph shows the cumulative distribution function, for which the value at a equals the area under the probability density curve to the left of a. Absolutely continuous probability distributions can be described in several ways.
Demographic statistics are measures of the characteristics of, or changes to, a population. Records of births, deaths, marriages, immigration and emigration and a regular census of population provide information that is key to making sound decisions about national policy. A useful summary of such data is the population pyramid.
Population dynamics has traditionally been the dominant branch of mathematical biology, which has a history of more than 220 years, [1] although over the last century the scope of mathematical biology has greatly expanded. [citation needed] The beginning of population dynamics is widely regarded as the work of Malthus, formulated as the ...
The exploration of the content of a data set. The use to find structure in data. Checking assumptions in statistical models. Communicate the results of an analysis. If one is not using statistical graphics, then one is forfeiting insight into one or more aspects of the underlying structure of the data.
Population geography. Satellite image of Earth at night. Population geography relates to variations in the distribution, composition, migration, and growth of populations. Population geography involves demography in a geographical perspective. [a] It focuses on the characteristics of population distributions that change in a spatial context.
The size of an organism or particle is typically measured using a physical characteristic such as length, width, or mass. The size–frequency distribution is then plotted on a graph, with the size of the organisms or particles on the x-axis and the frequency of occurrence on the y-axis. This results in a curve that represents the distribution ...